Improvements of the pantograph-catenary interaction: numerical simulations and experimental tests on the Italian high-speed overhead contact line

The problem of accurately simulating the pantograph-catenary interaction is of crucial importance in the design and understanding processes of the overhead contact line (OCL) dynamics. In particular, OCLs are known to be very low-damped structures, with a high modal density in the low-frequency region. This has a significant impact on the interaction with the pantograph, especially in the high-speed case. Therefore, being able to optimize the damping distribution of such structures might be an efficient way of improving the current collection quality of existing lines. This theoretically means gaining a smoother contact between the OCL and the pantograph(s), as well as the possibility to increase the train speed above the present limits, still in compliance with the current operational rules. This is a particular issue in the case of two running pantographs, where the rear one (trailing) usually behave worse than the front one (leading). In this work, a new tool for simulating the pantograph-catenary interaction is introduced, called Cateway. The software is first validated according to the standard EN50318, and then adopted to evaluate the effects of localized alterations in the damping distribution using improved damping droppers. Experimental functional tests are also conducted on a real overhead contact of RFI line to identify its damping distribution and to test the capability of the abovementioned devices to increase its damping properties in the frequency region of interest. The results of these tests give useful insights about the dynamics of the OCL structure, and on the enhanced damping capability of the tested device. Eventually, Cateway is adopted to replicate the experimental outcomes, and to simulate the effects of the improved damping droppers on the contact force. Results show remarkable improvements of the current collection quality, especially for the trailing pantograph in the case of two running pantographs.